The Parthian kings were called brothers of the sun and moon, hence the star and crescent on their coins. The royal wart was the sign of true membership in the Arsakid family and was used at least as early as the time of Orodes II to establish legitimacy to the king’s claim to the throne. In modern terminology it is called a tricoepithelioma, a hereditary lesion on the forehead, known to be passed on for as long as one hundred years. In the Arsakid family, according to tradition, it lasted throughout the dynasty, almost five hundred years. It is probable, however, that the later kings’ claim to the royal wart was counterfeit, with the lesion on later tetradrachms replaced by a lock of hair.